FIG. 18 is a cross-sectional view of a simple-matrix-type liquid crystal display (LCD) panel in which glass is used as a material for substrates. This simple-matrix-type LCD panel includes a SEG substrate 101 on a segment electrode arrangement side, a COM substrate 102 on a common electrode arrangement side, a liquid crystal layer 103 provided between the SEG substrate 101 and the COM substrate 102, a sealing member 104 for adhesion between the substrates 101 and 102, and spacers 105 dispersed in the liquid crystal layer 103.
The foregoing SEG substrate 101 is normally formed by providing on one surface of a glass substrate 106a transparent electrodes 107a (segment electrodes), an insulating film 108, and an alignment film 109a in this order, as well as providing a phase difference polarizing plate 110a on the other surface of the substrate 106a. 
On the other hand, the foregoing COM substrate 102 is formed by providing on one surface of a glass substrate 106b color filters 111, a transparent electrode (common electrode) 107b, and an alignment film 109b in this order, as well as providing a phase difference polarizing plate 110b on the other surface of the glass substrate 106b. 
Upon fabrication of a COM substrate 102 and a SEG substrate 101 that are in pair, a process relating to components provided only on one substrate is unnecessary for the other substrate. In such a case, while a certain operation is carried out for formation of such a component on one substrate, usually nothing is done with respect to the other substrate on which the component is not provided.
FIGS. 19 and 20 show an example of a process flow for the foregoing LCD panel fabrication.
FIG. 19 is a process flow about operations around the formation of the insulating film 108, which is provided only on the SEG substrate 101. The SEG substrate 101 is subjected to cleaning, insulating film printing, and baking as processing operations for formation of the insulating film 108, but these processing operations are not applied to the COM substrate 102. Thereafter, processing operations (cleaning, alignment film printing, baking) for alignment film formation are applied to both the SEG substrate 101 and the COM substrate 102. Specifically, processing operations (cleaning, alignment film printing, baking) shown in FIG. 19 for forming an alignment film 109a are applied to the SEG substrate 101 after formation the insulating film 108. On the other hand, since an insulating film is not provided on the COM substrate 102, processing operations (cleaning, alignment film printing, baking) shown in FIG. 19 for formation of an alignment film 109b are applied to the COM substrate 102 after formation of color filters 111 and transparent electrodes 107b. 
FIG. 20 is a process flow about before and after panel alignment of the SEG and COM substrates 101 and 102. Spacers are distributed on the SEG substrate 101. On the other hand, the COM substrate 102 is subjected to sealing material printing and leveling (heat treatment).
As described above, in the process before panel alignment, the SEG and COM substrates 101 and 102 are subjected to different processing operations from each other, respectively. However, even if the SEG and COM substrates 101 and 102 are thus subjected to different processing operations, respectively, there arises no problem since they are formed with glass as a substrate material that is hardly warped and that ensures accuracy.
In the case where flexible substrates made of an organic material such as plastic are used in the place of the glass substrates 106a and 106b, irreversible shrinkage of substrates occurs in a heating process and thereafter in a cooling process to room temperature again, thereby causing changes of the size to be induced. This could result in that the SEG and COM substrates 101 and 102 that have been completed through all the processing operations have different pattern sizes.
A graph of FIG. 16 shows how the size of a plastic substrate made of PES (polyether sulfone) changes in the case where a series of treatments including heat treatment at 150° C. for 60 minutes and a cooling treatment to room temperature while maintaining a dry state is repeatedly applied to the plastic substrate. Viewing changes in the size of the plastic substrate when cooled to room temperature, it can be seen that shrinkage of the plastic substrate is promoted as the number of times of repetition of the foregoing treatments in series increases.
Furthermore, an inorganic material such as plastic has a drawback of swelling by absorbing moisture, unlike glass. Therefore, during the cleaning treatment using water as a cleaner, a change in the size of the plastic substrate (swelling due to absorption of moisture) is induced, thereby causing a phenomenon similar to that caused by the heat treatment, that is, the problem that substrates in pair (the SEG and COM substrates 101 and 102) have different pattern sizes.
A graph of FIG. 17 shows expansion (swelling) of a plastic substrate made of PES due to moisture absorption and shrinkage of the same due to drying that was measured for reference by the inventors of the present application. In the case where the plastic substrate is left in an environment at a temperature of 25° C. and a humidity of 65%, and in the case where it is soaked in warm water at a temperature of 40° C., quantities of moisture that the plastic substrate absorbs are different, and hence, dimensional changes they exhibit are also different. The dimensional changes herein are substantially equal to those in the case where a heat treatment is applied as shown in FIG. 16.
As described above, in the case where plastic substrates are used as the SEG and COM substrates 101 and 102, dimensional changes occur to them due to shrinkage caused by heat treatments, or due to moisture absorption upon leaving or cleaning. For example, in the case of a 300 mm-long substrate, a dimensional change of 0.1% is a dimensional change of 0.3 mm. In the case where a dimensional change at such a level is caused to one of substrates in pair, it is difficult to align the substrates so as to achieve accurate pattern alignment, and to produce a plurality of LCD panels with satisfactory accuracy from the combined substrates.
FIG. 21 shows a process flow for panel cutting, which is a process for cutting out a plurality of LCD panels after the panel alignment of the SEG and COM substrates 101 and 102. This panel cutting process does not cause a defect due to a size difference between the SEG and COM substrates 101 and 102.
However, in the case where plastic substrates are used as the foregoing SEG and COM substrates 1 and 2, swelling due to moisture absorption occurs to the plastic substrates in a stand-by state for the cutting, being left under room environmental conditions. Therefore occurs a problem that cutting dimensions cannot be determined. Generally, the LCD panel fabrication process is executed under intentionally moistured conditions (relative humidity: 60% to 70%), so as to suppress generation of static electricity. Therefore, in the case where plastic substrates are used as the foregoing SEG and COM substrates 1 and 2, the plastic substrates when being left in a room environment during a stand-by time, absorb moisture and swell. Accordingly, in the case where plastic substrates are used as the foregoing SEG and COM substrates 1 and 2, influences of the dimensional change due to moisture absorption as shown in FIG. 17 are not ignorable.
As means to solve the foregoing problems, the following techniques are proposed.
The Japanese Publication for Laid-Open Patent Application No. 64038/1995 (Tokukaihei 7-64038 [Date of Publication: Mar. 10, 1995]) discloses a method for producing with satisfactory accuracy a plurality of LCD panels from a large-size substrates including plastic films. In this method, as shown in FIG. 22, a base 121 with rigidity on which a plastic film 123 is provided is used as one substrate 122, among two substrates. The other substrate 124 formed in a panel size is aligned with the substrate 122, at a pattern position thereof. Incidentally, in FIG. 22, 125 is a transparent electrode, 126 is a liquid crystal injection port, and 127 is a line (cut-out line) along which a panel is cut out through a subsequent process.
In such a method, the panel alignment accuracy for the two substrates is not necessarily achieved throughout an entirety of one large-size substrate (one substrate), but may be achieved within a tolerable range throughout one panel-size small substrate (the other substrate) Therefore, since a position correction can be executed at a stage of panel alignment for combining each panel-size small substrate to the large-size substrate, flexible LCD panels can be produced with satisfactory accuracy.
However, in the arrangement of the foregoing Tokukaihei 7-64038, in the case where many panels are to be produced from one large-size substrate, panel alignment of a small-size substrate has to be carried out many times, thereby increasing a processing period for the panel alignment. Furthermore, an increase in the costs due to an increase in the number of manufacturing apparatuses is also expected. Furthermore, a capacity of one aligning device varies depending on the panel size. For these reasons, there arises a problem that the efficiency of the manufacture line lowers.
On the other hand, in the case where only a few panels are taken out of one large-size substrate, that is, in the case where large-size panels are obtained, a problem that occurs in the case where the process for the glass substrate is applied to small-size substrates (that is, a dimensional difference between two substrates that stems from a difference between processes of fabrication of the two substrates) arises, and dimensional errors on the small-size substrate side exceed a tolerable range. Consequently, a problem that a flexible LCD panel cannot be produced with a desired pattern accuracy.
In other words, the foregoing methods are aimed for fabricating a plurality of flexible LCD panels from a large-size substrates, and do not fundamentally solve dimensional errors due to dimensional changes (swelling/shrinkage) of two substrates to be aligned with each other. Therefore, they are not to achieve improvement of size accuracy throughout the whole substrate. Therefore, the foregoing methods are inappropriate in the case where only a few panels are taken out of large-size substrates, particularly in the case where a single large-size LCD panel is produced from large-size substrates.